The instant invention relates to a laser beam duct pressure controller system and more particularly to a pressure control system for maintaining a spatially uniform pressure in a flowing gas volume which is subjected to temporal pressure variations.
For the typical airborne laser system, the laser telescope, or beam extender, is located within a rotatable turret which is mounted external of the aircraft, and the laser beam exits through an opening, or aperture, in the turret side wall. The output from the laser device, which is carried inboard of the aircraft, is relayed to the beam expander through an enclosed laser beam duct which is purged by a flow of conditioning gas, in order to minimize optical distortions along the beam path. At least a portion of the lasr beam duct communicates directly with the turret compartment (i.e., cavity or void in the turret), which, in turn, senses the local external pressure through the turret aperture. As the laser telescope look-angle changes, such as during turret tracking and acquisition operations, the turret compartment pressure will vary with time, and these pressure changes will propagate through the gas within the laser beam duct. Since typically a transverse conditioning gas flow is used in the laser beam duct (i.e., flow normal to the duct axis), the axial pressure gradient introduced by changes in turret compartment pressure can induce significant axial motion of the gas in the laser beam duct, and thereby lead to serious optical degradation.
Therefore, what is needed in the art and is presently not available is a means (e.g., an apparatus, system, or the like) for eliminating the aforementioned undesired, and optical degradation causing, axial flow of the conditioning gas.